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Comments on structural specification (was Re: document pubication schedule)

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Mon, 22 Oct 2007 18:18:03 -0400
Message-Id: <F9A27E86-A5E8-4D40-8E77-FE17CF9F0247@cs.rpi.edu>
Cc: jjc@hpl.hp.com, public-owl-wg@w3.org
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>

Peter asks that we bring up comments on the documents proposed to be  
moved - here's my major comments on the structural specification.

1 - Structural Specification.  I am not convinced this document moves  
forward the use of OWL, and instead forces an entirely new syntax on  
a community that is finally learning to use N3 and RDF as OWL specs,  
which is also what most tools currently consume and produce.  I think  
the drawings are quite useful, but I find the syntax to be difficult  
to teach and to use as it is not the natural thing for me the way it  
is for some people trained in this area.  It's not that I couldn't  
learn, but I question why, to learn to use a Semantic Web language I  
have to learn yet another syntax.
  I also object to some of the same things in this syntax that I  
objected to when an attempt was made for OWL 1.0 to use the "abstract  
syntax" normatively.
   i.  While it is nice that there is a notion of locality in the  
document, I think it a positive and desirable feature that OWL  
documents can have properties and classes intermixed and partially  
defined in many parts of a document.  The non-linear nature (for lack  
of a better term) of RDF is a positive I don't want to lose
  ii. The namespace issues that Jeremy mentions are quite blurred in  
this document
  iii. I think the document introduces many terms into the structural  
definitions that may or may not end up having actual vocabulary terms  
associated with them in the OWL/RDF that results.  This means that  
someone trying to learn OWL through this document cannot understand  
easily by the end what is, and is not, in the vocabulary.  For  
example, picking one of many at random, will "owl:dataComplementOf"  
be in the set of terms we are recommending or won't it? there are  
many other features that make it hard to know what is actually being  
proposed as language structures and what aren't
  iv. Appendix A makes some strange claims like:

"For example, one can assert the following axiom in OWL 1.0:

ObjectProperty(hasPart inverse isPartOf) "

which is not true - only the abstract syntax of OWL (not part of the  
recommendation as a normative way to exchange OWL documents) allows  
that - in OWL one would say (in N3, I really should do it in proper  
RDF but this is faster:)

:haspart a owl:ObjectProperty;
    inverse :isPartOf.

So I believe the document, without more explanation of what it is  
about (i.e. is this a replacement for the Abstract Syntax or  
something more) and without changes that make it clear what was and  
was not in OWL 1.0 will confuse a large portion of OWL users and  
require considerable effort and learning for those who have already  
learned and use OWL regularly.

  v. The use of authors, over editors, is somewhat at odds with the  
use of these terms in the W3C (http://www.w3.org/2001/06/manual/ 

In short, I don't see the structural syntax being needed on the Rec  
track without at least a significantly better explanation of its use,  
its need, and its role in the new recommendations (i.e.  is it a  
presentation syntax, is it the definition of new terms, is it the  
abstract syntax for logical clarity.
Received on Monday, 22 October 2007 22:20:47 UTC

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